ViON have produced a 100TB DRAM solid state drive, which they claim to be the largest flash memory-based storage box in the world.
The HyperStor-6200 uses both Hitachi Data Systems and Texas Memory Systems technology - think RamSan 6200 - and provides five million I/Os per second (IOPS) with 60GB/sec bandwidth. It is a monster …

... or you are just not getting it.

Of course if you can build a big enough USB farm, park some ZFS on it and actually get some USB bus speed that can drive it, and you remember that you don't have any moving parts, you'r right, it is just not that cool.

Raid can be about protection

And of course mirroring is not a complete backup solution, but it does offer protection, protection against hardware failure.

And of course it is wrong to say that RAID is just about availability, in fact more often it is about performance, whether striping on flash memory gives performance is probably worthy of investigation.

So what

Ah, the old days

I unforget installing a 'ram disk' on Baker Perkins' IBM mainframe. It was the size of a couple of filing cabinets, and looked like a 10" removable platter disk drive to the OS, while being a hundred times faster.

It used about five horse-power's worth of electricity and contained something like 25Mb as I recall. Or would have done if the tight bastards had ordered it full.